The present invention relates to a semiconductor device and a method for controlling the same.
An electronic instrument such as a portable telephone is reduced in size by providing a liquid crystal system in the electronic instrument. A further reduction of power consumption can be realized by strictly performing drive control using a driver (integrated circuit or semiconductor device in a broad sense) which drives a liquid crystal panel which makes up the liquid crystal system.
A control register is provided in the driver. Drive control corresponding to control data is enabled by setting the control data in the control register, whereby further strict drive control can be realized. As examples of the control register, a control register for setting a region to be displayed, selecting the data line to be driven, selecting the shift direction of display data to be supplied, setting display output timing, or the like can be given.
The driver is connected with a micro processor unit (hereinafter abbreviated as “MPU”) (display controller). As disclosed in Japanese Patent Application Laid-open No. 2001-222249, the MPU sets the control data in the control register of the driver at the time of power-on or initialization or during a display period. The driver generates a control signal set in the control register, and performs drive control based on the control signal.